märgsöövitust

Märgsöövitust, also known as wet corrosion, is a type of electrochemical corrosion that occurs in the presence of an electrolyte, typically water. This process involves the oxidation of a metal and the reduction of another species, usually oxygen or hydrogen ions, forming a galvanic cell on the metal surface. The presence of moisture is essential for the ions to migrate and complete the electrical circuit, allowing the electrochemical reactions to proceed.

The rate of märgsöövitust depends on several factors, including the type of metal, the concentration of dissolved ions in the electrolyte (such as salts or acids), temperature, and the availability of oxygen. Different metals have different electrochemical potentials, which dictates their tendency to corrode. For example, in a bimetallic contact, the less noble metal will act as the anode and corrode preferentially. Dissolved salts, like sodium chloride, significantly increase the conductivity of water, accelerating the corrosion process.

Common examples of märgsöövitust include the rusting of iron and steel in humid environments or when exposed to rain. This is a visible manifestation where iron oxidizes to form hydrated iron oxides, commonly known as rust. Other examples include the corrosion of copper in moist air, leading to the formation of a green patina, or the corrosion of aluminum in saline solutions. Preventing märgsöövitust often involves protective coatings, such as paint or galvanization, or by controlling the environmental conditions to minimize moisture and the presence of corrosive agents.